Mmm, good call on that Boulder throwing thing lmao. He could just flick it away... Instantaneous is simply fast speeds though, has been explained in the anime before briefly. Also, the Surfer CAN be separated from his board, which in turn would render him powerless. Understand however, that Goku would lose simply because he would never allow that to happen. He likes to fight strong opponents lol. Never takes advantage like that.